This invention relates to a yieldable closed or opened support frame for mine passages and the like, in the form of a plurality of adjoining inner and outer hollow segments frictionally joined together at opposite ends, and more particularly to means for moving the adjoining segments apart during a disassembly operation.
In such a yieldable roof support structure, for example, of the type set forth in the aforementioned related application, the entirety of which being specifically incorporated herein by reference, the overlapping ends of the adjoining inner and outer segments may become so tight when the frame is subjected to heavy overhead pressures in the mine passages or tunnel, that the segments are not capable of being easily disassembled for further reuse. Although the overlapping ends of the other segments are sufficiently elastic so as to permit distortion without permanent deformation during assembly with the inner segments, the extent of the overlap increases under the weight of the earth overhead during extended periods of use, such that movement of the joined segments apart may damage the segments thereby prohibiting their reuse.